This invention relates to vacuum adjustment devices, and more particularly to a vacuum adjustment device for a breastpump.
This invention was developed with particular application to controlling the vacuum, i.e., negative pressure, within the hood (or shield) of a breastpump. As is well known, vacuum is generated within the downstream part of a funnel-shaped shield within which the breast is received, to draw upon the breast in a manner reminiscent of suckling, and thereby express milk. The milk is typically collected in a bottle or other container, for later use.
There have been mechanisms developed in the past for applying some control over the amount of vacuum (negative pressure) generated at the breast. The present invention was conceived as a considerable improvement over the prior art, providing the user with a continuously variable vacuum adjustment in an easily manipulated device.
It is accordingly a principal objective of the present invention to provide an improved vacuum adjustment mechanism for controlling airflow into a chamber which is subject to negative pressure, such as the chamber of a diaphragm pump which is generating vacuum for a breast shield assembly. The invention could, however, readily be adapted to some other part of the breastpump.
In one form of the invention, there is an air inlet conduit communicating with the chamber. A channel is formed in a base member, with the channel having a longitudinal length and a dimension perpendicular (e.g., radial) to that length. The perpendicular dimension varies from a minimum to a maximum, which thereby varies the cross-sectional area of the channel. The channel has a bottom and is open, such as along a channel top.
An airhole is formed in the channel, most preferably in the bottom at the point of the maximum dimension. The airhole communicates with the air inlet conduit to the chamber. A rotary member is mounted on the base member. The rotary member has an internal channel, most preferably one having a portion thereof extending across the longitudinal length of the base member channel, and overlies the channel top. The internal channel of the rotary member communicates with an air source, such as ambient air.
The rotary member serves to move its internal channel along the longitudinal length of the base member channel, to thereby regulate airflow into the base member channel depending upon where the internal channel is positioned between the minimum and maximum dimensions. Of course, the internal channel of the rotary member and the base member channel could be reversed with one another, so long as the two are capable of relative rotation.
An embodiment of the inventive vacuum adjustment device furthermore provides an internal channel which has its greatest area (e.g., depth) in the middle, with a decreasing channel dimension on either side thereof. This yields an adjustment feature which is the same regardless of which direction the rotary member is rotated.
The term xe2x80x9cperpendicularxe2x80x9d relative to the longitudinal length is meant to include any relative dimensional change of the channel or groove. While a change in depth is disclosed in the following embodiments, the dimensional change could be width, or a combination of both length and width.
Other features and advantages of the present invention will become apparent from the detailed description that follows taken in conjunction with the drawings, described below.